MSI mode: message-signalled interrupts and DPC latency

Frost LIVEGPUProUndo: YesUpdated Oct 8, 2026View as Markdown

Short answer

Updated Oct 8, 2026

MSI mode sets MSISupported to 1 under the device's Interrupt Management\MessageSignaledInterruptProperties key, switching a device from legacy line-based interrupts to message-signalled interrupts. It reduces DPC latency, which is the mechanism behind audio crackling and micro-stutter. This is one of a small number of registry tweaks from the old era that still has a real measurable effect.

In the app

Optimize Message Signal Interrupts (MSI)PRO

Registry

HKLMSYSTEM\CurrentControlSet\Enum\<device instance>\Device Parameters\Interrupt Management\MessageSignaledInterruptProperties

MSISupportedYour previous value1

What the switch writes. Your current value may differ. 2 more changes below.

What it does

Legacy interrupts use physical lines that devices can share. When several devices share a line, the OS has to poll each to find out who signalled, which adds latency and can serialise unrelated work.

Message-signalled interrupts let a device write directly to a memory address instead. No sharing, no polling, less time spent at high interrupt priority.

The device instance path is different on every machine, which is why this is fiddly to do by hand.

When it helps, and when it hurts

When it helps

Lower DPC latency, which is the direct cause of audio crackling accompanied by stutter.
Most noticeable on systems with many PCIe devices competing for interrupt lines.
Covers graphics cards and storage controllers, NVMe included, not just the GPU.

When it hurts

A small number of older devices misbehave with MSI enabled. Symptoms range from device instability to failure to resume from sleep.
It has to be applied per device and re-applied if the device is reinstalled, which is exactly the maintenance problem manual tweaking has.
Not every device honours the setting even when the key exists.

What it writes

Exactly what the switch changes, read from the app's source. Switching it off is what the app writes when you turn the tweak off again.

Registry values the switch writes.
Key and value	With the tweak	Switching it off
HKLMSYSTEM\CurrentControlSet\Enum\<device instance>\Device Parameters\Interrupt Management\MessageSignaledInterruptPropertiesMSISupportedLets the device raise interrupts by writing a message rather than asserting a shared physical line. The app sets it for every graphics card, SATA controller and storage controller (NVMe included) that Windows lists.	1	Your previous valueSaved before the change, or deleted if there was none.
HKLMSoftware\FrostTweaks\MSI\<device instance>PrevThe app's own backup of the device's earlier setting, so switching the tweak off can put it back.	The previous MSISupported value	Stays The previous MSISupported valueSwitching it off leaves it.
HKLMSoftware\FrostTweaks\MSI\<device instance>PrevMissingWritten instead of Prev when the device had no MSISupported value, so switching the tweak off deletes it again.	1	Stays 1Switching it off leaves it.

From the app's source (msi.hpp), app 2.0.0, checked Oct 8, 2026.

How to undo it

In the app: Yes

Switching it off restores each device's previous MSI setting, which the app saves before changing it.

Set MSISupported back to 0 for the affected device and reboot. Frozen Tweaks stores the previous value per device instance, including the case where the value did not exist at all, so switching it off restores the true original state rather than guessing at 0.

Changing several settings at once? The app's Make a restore point button, on every plan, makes a Windows restore point before you start.

Verdict

Genuinely worth applying, and one of the few places where a tool is meaningfully easier than doing it by hand, because reverting requires remembering the prior state of every device you touched.

In the app